3-Amino-Imidazopyridines by a Microwave-Assisted Synthesis

Significance

A microwave-assisted, Pd-catalyzed four-component synthesis of 3-amino imidazopyridines in a one-pot process is reported. In the initial process, a three-component Ugi reaction of a 2-aminopyridine with an aldehyde and an isonitrile leads to a 3-amino imidazole. The subsequent Pd-catalyzed Suzuki coupling in the same pot is possible due to the compatibility of the boronate with the mild Lewis acid conditions. An attempt to perform the reaction not in this sequence but by carrying out the Suzuki coupling before cyclization was not feasible. Paraformaldehyde was used as part of a three-component Ugi reaction for the first time.